Milan Grygar. Kresba 18 A 17
Signed. Produced in collaboration with the sound laboratory of the “ÚTDU ČSAV” Ústav pro teorii a dĕjiny umĕní Československé akademie vĕd (Institute for Art Theory and Art History of the Czechoslovak Academy of Sciences) in Prague. Single, Supraphon 1599871. Czechoslovakia 1976